The present invention relates to an improved method of washing clothes and similar items, to a portable apparatus for performing that method, and to novel fluidic oscillators particularly suited for use in that apparatus.
Commercially available clothes washing machines generally employ either an agitation or tumbling action to effect cleaning. Agitation is generally performed by rotating blades or vanes which produce turbulent convection of water and/or detergent through the material to be cleaned. Tumbling is generally effected by a rotating drum which constantly tumbles the material through a water solution. In both cases the operating mechanism requires: electrical energy to drive the machine; and a mechanism with moving parts which are subject to wear and eventual failure. Moreover, mechanisms of this type are both relatively expensive and sufficiently massive to preclude portability. Portability is important to permit utilization by travellers who have limited access to permanently installed washing machines and by apartment dwellers and the like whose residences are subject to restrictions which prevent installation of conventional washing machines.
Another problem inherent in conventional washing machines resides in the fact that they are designed to wash multiple-item loads, thereby rendering them inefficient for cleaning one or two small items. Thus, the tendency is to collect soiled clothes until a load of sufficient volume is gathered to permit efficient use of a conventional washing machine. This severely limits the availability of garments.
Still another cleansing action which is effective with clothes is microflotation. In this cleansing action air bubbles are intermixed with the water and/or detergent and are permitted to rise to the surface. In so doing they attract dirt particles in the water solution and from the clothes so that the dirt is also floated to the surface where it can be readily removed. Microflotation is not feasible in most commercial washing machines because the water solution is continuously re-cycled through the washing tank. As such, any dirt floated to the surface could not be removed but instead is recirculated back into the wash solution.
It is therefore an object of the present invention to provide a method and apparatus of washing clothes and the like which utilizes agitation, tumbling and microflotation, all in combination, yet which does not employ moving parts and does not require electricity for operation.
It is another object of the present invention to provide an apparatus for washing clothes and the like which is relatively inexpensive and portable.
It is still another object of the present invention to provide a clothes washing method and apparatus which can be utilized anywhere where a source of water under pressure is available and which is efficient for washing even a single garment.
Attempts have been made in the past to eliminate the need for moving parts in clothes washing machines. For example, U.S. Pat. No. 3,358,478 to Heskestad describes utilization of a fluidic amplifier which delivers a pair of alternately pulsating jets radially into a wash tank to effect agitation of the wash solution. The fluidic amplifier eliminates the need for rotating blades to effect agitation but nevertheless requires an electrically-operated pump for the purpose of recirculating the wash solution. Moreover, the Heskestad approach provides only agitation to effect cleansing; there is no tumbling or microflotation action to increase the efficiency of dirt removal.
Another prior art washing machine employing a fluidic amplifier to deliver water pulses to a wash tank is disclosed in U.S. Pat. No. 3,444,710 to Gaugler et al. This approach requires that the pulses be delivered substantially tangential to the tank wall and into a load basket which rotates about a vertical axis. This approach also effects agitation; however, efficient cleaning is made possible only by rotating the basket, which requires an electrically operated motor. Further, the basket rotation is opposite to jet flow and counteracts any tendency of the pulsed liquid jets to force the clothes to flow through the water; therefore, no tumbling of the clothes, as such, occurs. Still further, microflotation is not suggested by Gaugler et al.
Although not useful as a clothes washer, another fluidic washing machine is disclosed in U.S. Pat. No. 3,620,050 to Glasgow. That patent describes apparatus suitable for cleaning solid objects and comprises a basin having sidewalls which are sharply inclined and converge down toward the cleaning region. Liquid pulses from one or more fluidic oscillators are directed substantially radially toward the center of the cleaning region where an object to be cleaned remains throughout the cleaning operation. An overflow outlet permits continuous draining of the liquid from the basin. Cleaning is effected by agitation of the bath liquid by means of the high frequency liquid pulses delivered from the fluidic oscillators; the action is analogous to the cleaning effect produced by ultrasonic baths. Moreover, Glasgow describes a reaction by air bubbles on the dirt, implying a microflotation effect. As described above, Glasgow's apparatus is not suited for washing clothes. Specifically, cleaning in Glasgow's apparatus is effective only if the object being cleaned remains stationary at the bottom of the funnel-like basin. Moreover, the basin is structured to inhibit any tumbling-type movement of clothes. Further, although Glasgow suggests that air bubbles can be drawn into the pulsating streams, there is no suggestion in the patent as to how this may be accomplished; in this regard, the oscillators illustrated in Glasgow's drawings are not provided with any means which will permit the pulsating streams to draw ambient air into the streams. Consequently, while Glasgow has apparently recognized the advantage of microflotation in a washing apparatus, the Glasgow patent does not disclose how this is to be effected.
It is therefore another object of the present invention to provide a clothes washing apparatus in which a fluidic oscillator effects both agitation and tumbling of the load and readily introduces air bubbles into the cleaning tank to effect microflotation.
It is still another object of the present invention to provide a fluidic oscillator capable of delivering liquid pulses and which efficiently causes entrainment of relatively large amounts of ambient air by these pulses prior to delivery.